A SatyaYuga Avatar
The younger brother of Hirṇayakṣa, Hiraṇyakaśipu wanted revenge on Viṣṇu and his followers. He undertook many years of austere penance to take revenge on Viṣṇu for the death of his brother. Brahma thus offers the demon a boon and Hiraṇyakaśipu asks for immortality. Brahma tells him this is not possible, but that he could bind the death of Hiraṇyakaśipu with conditions.
Hranyakashipu asks that he not be killed by man or animal, inside or out, day or night, on earth or the stars, with a weapon either living or inanimate.
Vishnu descended as an anthropomorphic incarnation, with the body of a man and head and claws of a lion. He then disembowels the rakshasa at the courtyard threshold of his house, at dusk, with his claws, while he lay on his thighs.